Grinding machine for paper pulp



me 16g 393@ F. LORD www GRINDING MACHINE FOR PAPER PULP Filed Sept. '7, 1935 2 Sheets-Sheet l 29 29 l 2 26 E i 28 27 30 f8 29 l :t I /f 5 1 I 18 2 34 g 9\T F 9 34 e e 28 5 g f 26 l` i I'- Rwff' n *v 1, "t" l-t *"*UJ-f",

jun@ 16, F QRD QQQ@ GRINDING MACHINE FOR PAPER PULP Filed Sept. 7, 1955 2 Sheets-Sheetl 2 mmMMoL/m @WLM JI far/1g,

Patented June 16, 1936 UNirEo GRINDING MA acaso FOR PAPER PULP Frank Lord, clie, England application september i, 1935, sei-iai No.' casos This invention relates to that kind of grinding machines, for paper pulp wherein there are superposed rotary grinding discs having grinding blades on the under sides and propeller vanes on the upper sides, the said discs being provided in a i stationary casing provided with' grinding blades and guide varies, and the paper pulp being forced upwards under pressure through the casing so as to travel radially outwards between the cooperating grinding blades and then travel radially inwards between upper sides of the rotary discs and the undersides oi parts of a stationary casing.

The object of my invention is to avoid the possibility of any pulp lodging and ceasing to travel' inwardly to the succeeding higher grinding blades.

In accordance with my invention, a grinding machine for paper pulp has disc-like walls which together kwith the said guide vanes form inwardly extending passages for the pulp, the said walls also cooperating with outwardly acting propeller -vanes provided on the upper sides of the rotary i discs to prevent entrance of pulp to and lodgment of pulp on the upper surfaces of the rotary discs. The said walls are preferably dished to increase the height of the passages towards the centre of the casing means and thereby compensate for the reduction in width of the said passages towards the centre.

I attain the hereinbefore stated object by the 0 means hereinafter described and shown in the annexed drawings wherein- Figure 1 is a view in vertical section of a grinding machine. for paper pulp.

Figure 2 is a detached plan view of the lower part of a stationary grinding disc.

Figure 3 is a detached plan view, regarded from below, of a part of the casing.

Figure 4 is a detached plan view of a rota grinding disc.

The machine shown in the drawings comprises a frame i in which is mounted a vertical shaft d provided with three rotary, conically dished grinding discs 2l having grinding blades 28 on their under sides and a :dat upper surface provided with scoop-like, radial propeller vanes 29. The grind ing blades 28 cooperate with grinding blades 26 provided on the upper surfaces of stationary dished, conical discs i3 having central apertures i8, the two uppermost stationary discs i3 having A inverted dished iianges I 6 forming part of the said casing, the under sides of which anges are opposed to the upper sides of the` rotary discs 21 and are provided with scoop-like, radial guide vanes 30. The pulp is forced under pressure, for example by means of a pump (not shown),

reat Britain November 29, 193i through the inlet 32, and up through the machine, and leaves the machine at the outlet 2B. Whilst passing through the machine, the pulp travels radially outwards between the cooperating grinding blades 26 and 28, and thenvradially inwards between the upper Y sides of the nges i6 and then through one of the central apertures i8 to to the next higher blades 28 and 28. n

A disc-like wall 33 is joined to the under edges' of the guide varies 3i@ to form with the said vanes passages extending from the mriphery oi each inverted dished ange i@ to the central aperture i8 provided in the corresponding stationary dished conical disc. The wall 33 extends beyond the inner ends of the guide varies 3d to separate the aperture I8 from the upper surface of the corresponding rotary-disc @Il The propeller vanes @9 on the rotary disc 2l lie below the wall 33 and are separated thereby from the guide vanes d@ on.l the inverted dished ange iii., The propeller vanes 29 on the rotary disc el act in an outwardly propellant direction and internal ribs ed are provided on the stationary dished conical disc is at the periphery thereof to form continuations or extensions of the guide vanes d@ on the iiange it.

The guide varies 30 on the ange i@ are of greater depth at'thecentre, the said wall @t therefore being of disc-like formation and the passages produced being deeper at the centre.

In operation the pulp forced upwardly under pressure through the lowermost central aperture it in each stationary disc is driven outwardly by the said pressure and centrifugal action, and during its outward travel it is und by the grinding blades 2S and 28. 35

The pressure and centrifugal action continues to act on the pulp after it has reached the periphery of the rotary disc 2l and forcibly :dings the pulp against the'ribs 3d which guide the pulp upwards and between the vanes 3d on the ilange 40 l, the following pulp forcing the preceding pulp through the passages formed by the vanes 3b and the wall 33 in an inward direction until it reaches the next higher central aperture it, up which it is forced to the succeeding grinding blades 2d and 45 28. The pulp'is prevented from leaving the ribs 34 and the entrance ends of the vanes @il on the ange i6 by the action ofthe vanes 29 on the upper side of the rotary disc 2l, the said action defeating any attempt of the pulp to enter and 50 iind lodgment between the upper surface or the rotary disc 2l and the under surface ot the wall 33.

Due to the increase in depth towards the centre of the es formed by the vanes 30 and the 55 wall 3l, the restriction in the width of the said passages due to their convergence from the peripheryof the ilange towards the centre is partially or wholly compensated for and the pulp can therefore ilow at a substantially uniform velocity through all parts oi.' the said passages.

Alternate of the guide vanes 30 may be formed shorter than the others to assist in preventing any constriction oi' the iiow ot pulp towards the centre.

I claiml. In a paper pulp grinding machine having superposed rotary grinding discs provided in a stationary casing, disc-like walls which together with the guide vanes provided on the stationary the reduction in width of the said passages to- A wards the centre.

FRANK LORD. 

